Agilex™ 5 Known Issue List

ID 849494
Date 11/24/2025
Public
Document Table of Contents

2.1.1.10. Reduced Reference Clock Frequency Options for Certain Output Frequencies in GTS System PLL Clocks IP

Description

Some reference clock frequencies listed in the drop-down list are not valid for certain GTS System PLL Clocks IP output frequencies. Selecting an invalid reference clock option results in incorrect GTS System PLL Clocks IP output frequencies. The invalid reference clock frequency options are available in Quartus® Prime Pro Edition software version 25.3 and earlier. The invalid options will be removed in the future release of the Quartus® Prime Pro Edition software version.

Workaround

There is no workaround. Altera offers a TCL script to verify if the reference clock frequency selected in the GTS System PLL Clocks IP is valid. If the reference clock frequency is not valid, the script recommends the following alternatives:
  1. Provides a list of alternative reference clock frequencies while maintaining the same output frequency.
  2. Suggests two alternative GTS System PLL Clocks IP output frequencies while keeping the same reference clock frequency. You need to run the transceiver channels driven by the impacted System PLLs in custom cadence mode.
  3. In some cases, the script suggests retaining the same input and output clock frequencies. This option is possible only if you install the patch for Quartus® Prime Pro Edition version 25.3 or migrate to future versions of Quartus® Prime Pro Edition.
Copy the tcl script (find_mcnt.tcl) to each of the generated IP folders of the GTS System PLL Clocks IP in your Quartus® Prime Pro Edition project.
  • For Linux operating system, change the directory to the IP folder and execute the command tclsh find_mcnt.tcl.
  • For Windows operating system, run the script from the Tcl Console within the Quartus® Prime Pro Edition Software GUI.
Table 12.  Recommended Actions based on Design Status
Design Status Recommended Actions
Design not impacted Implement the following actions based on your design need:
  • If the design is final and you do not plan to change the System PLL output frequency or reference clock frequency in future versions, you do not need to take any further action.
  • If you want to change the design in the future, either migrate it to a future version of the Quartus® Prime Pro Edition, or install the patch for Quartus® Prime Pro Edition software version 25.3.
Design impacted Implement one of the workarounds suggested in the TCL script. In addition, migrate your design to a future version of the Quartus® Prime Pro Edition software. If you need to keep your design in Quartus® Prime Pro Edition software version 25.3, install the patch, regenerate the GTS System PLL Clocks IP and recompile your Quartus® Prime project.

Status

Table 13.  Device Status Table
Devices Affected Planned Fix

A5EC008xxxxxxxx

A5EC013xxxxxxxx

A5ED008xxxxxxxxCS

A5ED013xxxxxxxxCS

No planned fix

Refer to the associated Knowledge Base entry to download the TCL script and patch.